History & Classification of Languages; Difference between C and C++

History & Classification of Languages

Evolution of Programming Languages

Classification of Programming Languages:

1.1 Procedure Oriented Programming (POP)

• FORTRAN is the 1st POP Language
• Examples: C, FORTRAN, PASCAL
• Focus is on procedures/functions (what to do)
• Global data shared between functions → security risk
• Programs structured as a series of function calls

Problems with POP:

• Global data is accessible to all functions — no data security
• Not suitable for large, complex programs
• Difficult to model real-world entities

1.2 Object Oriented Programming (OOP)

• Simula is the 1st OOP Language (1960)
• Smalltalk is the only PURELY OOP Language
• C++ is a partial OOP language (also procedural)
• Examples: C++, Smalltalk, Java, C#
• Focus is on objects — data + behavior together

1.3 Object Based Programming

• Ada is the 1st Object Based Language
• Examples: Visual Basic, Ada, Modula-2

Has objects but lacks inheritance and polymorphism

1.4 Rule Based Programming

• Examples: PROLOG, LISP
• Used in AI, logic programming

C++ History

Difference between C and C++

C++ Enhancements over C

C++ Input/Output

#include <iostream>
using namespace std;

int main() {
    int x;

    // cin with extraction operator >>
    cout << "Enter a number: ";  // cout = console output; << = insertion operator
    cin >> x;                    // cin = console input; >> = extraction operator

    cout << "You entered: " << x << endl;

    // Multiple inputs
    int a, b;
    cin >> a >> b;
    cout << "Sum: " << a + b << endl;

    // String input
    string name;
    cout << "Enter name: ";
    cin >> name;       // stops at whitespace

    // String with spaces
    string fullname;
    cout << "Enter full name: ";
    getline(cin, fullname);    // reads entire line

    return 0;
}